Colored light-sensitive material and process of producing color pictures therewith



Patented May 26, 1936 COLORED LIGHT-SENSITIVE MATERIAL AND PROCESS OF PRODUCING COLOR PICTURES THEREWITH Bla Gaspar, Brussels, Belgium No Drawing. Application December 23, 1933,

Serial 29, 193

No. 703,829. In Germany December 2 9 Claims. (01. 95-6) for producing insoluble dyestuffs in the layer or for producing layers thus colored which are recolored by the subsequent chemical treatment.

It is known to employ osarones as filter dyestuffs. The invention, however, does not relate to the use of this substance but to hydrazo compounds of that kind which may be converted into azo dyestuffs.

The hydrazo compounds or compounds of equivalent eflect may be employed in difierent manners.

It is possible, for example, to produce light 111- ters by adding the hydrazo substances and subsequently converting these into azo substances.

If it is desired to produce photographic layers to support an image, a finished silver image may be impregnated with a hydrazo substance by immersion therein, and this hydrazo substance subsequently converted into an azo substance. At the point at which the dyestufi is to remain invisible, the azo dyestufi produced is destroyed locally, and this may take place at the points of the silver or the points free of silver,'dependent on the particular circumstances. After the immersion in the hydrazo substance, the dyestufimay be produced locally, for example at the points of the silver image, by conversion of the silver image, say, by conversion over lead chromate into an oxidizing substance.

Alternately the hydrazo dyestuflf-forming compounds may be incorporated in the emulsion prior to its application to the backing or support. It will be understood that in either case the hydrazo substance is uniformly dispersed throughout the emulsion layer during the immersion of the layer in the hydrazo substance.

For the production of colour-photographs, various methods may be adopted.

,According to one method particles of emulsion of different subsequent color and different sensitization may be distributed in the layer in the manner of screen images, with. or without filter dyestuffs, and the same then converted into the corresponding azo dyestuffs.

It is also possible to produce multi-layer color photographs having differently sensitized layers poured one upon the other. There may be produced in very simple fashion according to the invention films of the known kind sensitized on both sides for subtractive processes, in which one or more colored part-images are disposed on either side.

As an example of the dyestufi-forming substances employed according to the invention, reference may be made to benzol-hydrazo-w naphthol, a colorless body which may be converted into a red-orange azo dyestufi by slight oxidation. A hydrazobiphenyl may be converted by oxidation into a purple-red dyestufi. These hydrazo substances are known in large numbers. It is also possible to employ their derivatives, products of substitution and esters, for example acetyl derivatives. Beyond this hydrazo compounds may be produced which contain an azo group in the molecule. From a hydrazo compound of this kind, a diazo dyestufi is obtained by subsequent oxidation. The hydrazo compounds may also be produced from azo dyestufls by reduction. Examples ofoxidizing agents are ferric-chloride or nitrous acid.

The advantage of this method consists on the one hand that colorless or relatively colorless dyestuif-forming substances may be admixed, for example, with a photographic emulsion, these substances having no disturbing efiect on the exposure; and not until afterwards are the same converted in very simple manner into the dyestufi'. An additional advantage resides in the fact that insoluble dyestuiis for example may be incorporated in colloid layers by means of soluble intermediate products. The layers may be employed for photographic purposes in any desired fashion.

It is also possible to incorporate insoluble salts,

for example hydrazoaryl-sulionic acid compounds with alkaline earth salts or nitrogenous organic bases with cinchonine or quinoline in the layer. or emulsion respectively.

It will be understood that no restriction is made to the substances specifically referred to, and that various modifications 0! this process are quite possible within the meaning of the above description and the annexed claims without de parting from the spirit of the invention.

I claim:-

1. A photographic material for producing colored images, comprising a light-sensitive silver halide gelatine emulsion and a hydrazo substance.

2. A photographic material for producing colored images, comprising a plurality of silver halide gelatine emulsions in combination with hydrazo substances, the said emulsions being disposed in desired order on a support.

3. A photographic material for producing colored images, comprising a light-sensitive silver halide gelatine emulsion and a hydrazo derivative.

4. A method of producing color images which comprises incorporating a hydrazo compound in a silver halide gelatine emulsion layer, producing a silver image in the said emulsion layer, and treating the layer with an oxydizing substance to transform the hydrazo compound into an 9.20- dyestufi.

5. A method of producing color images which comprises incorporating a hydrazo compound in a silver halide gelatine emulsion layer, producing a silver image in the said emulsion layer, treating the layer with an oxydizing substance to transform the hydrazo compound into an azodyestufi, and treating with a dyestufi-destroying agent which destroys the said azodyestufi by reaction with the silver particles in proportion to the silver image produced in the layer.

6. In a method of producing color images by selective dyestuff reaction the step which consists in with the silver image, treating a sliver image layer containing a hydrazo substance uniformly dispersed in said layer with an oxidizing substance to transform the hydrazo substance into an azodyestufi.

7. A method of producing color images which comprises treating a silver image layer containing a hydrazo substance uniformly dispersed in said layer with an oxidizing substance to transform the hydrazo substance into an azodyestufi, and treating with a dyestuif destroying agent which destroys the said azodvestuff by reaction with the silver particles in proportion to the silver image produced in the layer.

8. A method of producing color images which comprises treating a silver image layer containing a hydrazo substance uniformly dispersed in said layer with an oxidizing substance to transform the hydrazo substance into an azodyestufl, and treating with a dyestufi destroying agent which destroys the said azodyestuif by reaction with the silver image in inverse proportion to the silver image produced in the layer.

9. A method of producing color images which comprises treating a silver image layer containing a hydrazo substance uniformly dispersed in said layer with an agent which converts the silver particles of said image into an oxidizing substance, and utilizing the oxidizing agent thus formed to transform said hydrazo substance into an emdyestuflf BELA GAsPAR. 

